Reverse circulation sub



June 25, 1963 J. G. JACKSON REVERSE CIRCULATION SUB Filed July 13, 1959 J0 HN 60H00 .MC/60A( INVENTOR.

WHA/VN a Mc MAN/GAL United States Patent O 3,095,052 REVERSE CIRCULATIGN SUB John Gordon Jackson, Denver, Colo., assigner to Gas Drilling Services Co., Los Angeles, Calif., a co-partnerslnp Filed July 13, 1959, Ser. No. 826,683 4 Claims. (Cl. 175-324) This invention 'relates generally to well drilling equipment and relates vmore particularly to reverse circulation tools or apparatus.

While the invention has particular utility in drilling equipment utilizing reverse circulation of air or other gaseous fluid or a mist of gaseous fluid and liquid, and is shown and described in such connection, it is to be understood that its utility is not confined thereto.

It is an object of the present invention to provide a reverse circulation sub adapted to eliminate plugging, bridging or sticking of the bit by the cuttings.

Another object of the invention is to provide a device of this character whereby quantities of fluids are removed from the bit thus allowing more air to circulate around said bit land effect faster drilling.

A further object of the invention is to provide a device of this character having pickup passages for fluids, liquid or gas or a mixture of both.

A still further object of the invention is to provide a device of this character that is extremely etlicient in picking up the cuttings and the like to be carried to the top of the well for disposal.

Another object of the invention is to provide a device of this character which, when used in high angle directional drilled wells will cause the sand and/ or cuttings to be rotated so that such material cannot f-all out by gravity.

It has been found that a mixture of air-water mist and lime serves as a highly effective fluid for use during drilling operations. The water acts `as -a lubricant and the lime is a corrosion inhibitor.

Still another object of the invention is to provide a device of this character which lowers the pressure on the formation.

Still another object of the invention is to provide a device of this character which tends to keep the side walls and the bit clean.

A still further object of the invention is to provide a device of this character wherein standard circulation may be used for certain purposes, such as, for example, liner cleaning.

Another object of the invention is to provide a device of this character that is relatively simple and sturdy in construction, and effective and reliable in operation.

The characteristics and advantages of the invention are further sufficiently referred to in connection with the following detailed description of the accompanying drawings which represent one embodiment. After considering this example, skilled persons will understand that variations may be m-ade without ldeparting from the principles disclosed, and l contemplate the employment of any structures, arrangements, modes of operation `or methods that are properly within the scope of the appended claims.

Referring to the drawings, which are for illustrative purposes only:

FIG, 1 is a side view of drilling apparatus embodying the invention and disposed in a well;

FIG. 2 is an enlarged longitudinal section thereof; and

FIG. 3 is a sectional view -taken on line 3 3 of FIG. 2.

Referring more particularly to the drawings, there is shown a rotary drilling bit, indicated generally at comprising a body 11 with depending arms to the inner ICC sides of Iwhich are operably mounted the cones or cutters 14.

At its upper end, the body 11 is provided with means for connecting the bit to the adjacent end of a drill string or the like. Any suitable means may be used, such as a box or other means, one such other means being shown and comprises a hollow, externally threaded pin 15 threadably disposed within the internally threaded box 16 at the lower end of a vtubular sub 18. The interior 19 of the pin is of substantially the same diameter as the passageZt) which extends longitudinally through the sub v1-8.

The head 11 is provided with an axial bore 21 therethrough which is of substantially smaller diameter than the diameter of the interior 19 of the pin` 15. A tube 22 is secured in the opening or bore 21 of the head 11 by -rneansof welding 23 or other suitable means and said tube extends from the lower side of the body 1-1 upwardly a substantial distance above the upper end of the pin Y1.5 so Athat there is an upper portion of said tube that extends upwardly in the lower end portion of the sub 18. Below the upper end of the tube 22 and inwardly of the box 16 there are a plurality of annular-ly spaced openings 25 in the wall of the sub 18, said openings being inclined upwardly and inwardly.

The upper end of the sub P18 is provided with a pin,

not shown, which is screwed into a box in the lower end of the adjacent pipe section 26 of -t-he drill string which extends upwardly to the surface land is connected to the usual operating equipment -for effecting rotation of the drill or bit.

-As reverse circulation is used, gaseous fluid under relatively high pressure is forced downwardly between the drill string and the wall 2S of the well, as indicated by the arrows 2.9 in FIGS. l and 2. The gaseous fluid travels to the -lower end of the well where the cutting is taking place and flows over the cutters and through the spaces thereabout-and into the lower end of the tube 22 as iudicated by the arrows 30 :and 32 respectively.

As the tube 22 is of relatively small diameter, the velocity of the gas passing therethrough will be substantially increased over the velocity thereof coming down the =annulus between the drill string and the well wall and, hence, there is a more elective picking up of the cuttings by this high velocity flow. Also, substantially larger cuttings will be entrained in the gaseous lluidand carried upwardly through the tube 22 from the upper end of which itis discharged into 'he passage 20 of the sub 18 and thence carried upwardly through the interior of the drill string. i

At the same time, gas from the annul-us between the drill string 'and the well wall will also dow yinto the interior 20 of the sub through the openings or ports 25. This ow will be at a relatively high velocity and the gas will pass upwardly in the iannulus 34 between the exterior of the tube 22 and the wall of the passage 20. As the gas from the passages or ports 25 passes the upper end of the tube 22, it creates a suction effect which serves to increase the elective flow of the gas and its capacity to carry the cuttings upwardly.

Since the interior of the string sections is of smaller effective size than the annulus between the exterior of lthe drill string and the well wall, 4the velocity of the gaseous fluid flowing upwardly through the drill string D is substantially greater than the velocity of said uid llowing down the tannulus between the string and well 'wall so that the cuttings are effectively carried upwardly to the surface for disposition.

It has been Kfound that with this arrangement, the bit is kept clean so that there is no plugging or bridging thereof, an effect due to the suction at the upper end of the tube 22. The pressure on the formation may be Patented June 25, v1963 lower with this arrangement and iluids are removed from the bit so as to allow more air to pass thereover and hence, permit faster drilling.

While air and/or other gaseous uid may be used as a drilling liuid, it has been ffound that a mixture of airwater mist and lime is very effective. The Water acts as a lubricant and the lime corrosion inhibitor.

Relative to the use of water mist or air-foam in drilling operations, water, either plain or containing a foaming agent, is injected into the air stream in lrather large amounts. This water travels down Ithe annulus between the 'well wall and the exterior of the drill string and so dilutes the cuttings that balling -action does not take place. The -foam water mist then carries the cuttings to the surface together with any water produced from the formations which are being drilled. In mist drilling the air is more than just saturated with Water. The conditions are more like that found in a driving rainstorm or the spray from a high pressure nozzle.

The purpose of putting lime into an air-water mixture is to prevent so-called oxygen corrosion of the drill string or drill pipe.

While only one port or passage through the 'bit or body is shown, it is to be understood :that there may be a plurality of Isuch por-ts connected to a jet tube such as the tube 22. The important factor is the suction applied to the bottom of the bit caused by the ow of a portion of :the liuid into the sub and past the upper, open end of the tube 22. Put another way, the total amount of the drilling uid is divided up, some passing about and through the fbit parts and some entering the sub to create suction which will be elective at the lower end of the bit -to increase the rate or speed of ow and'upward through the drill string. I

r[The tool may -be used `to clean a liner or` perforation and when thus used there is a simple jetting action out of the ports 25, standard circulation then being used. The Ibit could vbe drilling the formation which has lled into the liner and the jets blow out against the perforation of the liner.

Itis thought that the invention and many of its attendant advantages will be understood from the Iforegoing description and it is believed that it will be apparent that various changes may be made in the form, construction, arrangement of the parts, and of the method of the invention without departing from the spirit and scope thereof or sacrificing all of its material advantages, the embodiment hereinbefore described being merely for purposes of illustration.

I claim:

'1. Apparatus for drilling wells and :the like, comprising: a rotary bit having a head with an axial opening therethrough,` said head having depending arms, cutter elements operably mounted on said arms, vand an externally threaded pin extending upwardly from the upper 'endA of said head and having an upwardly opening recess therein; an upwardly extending tube secured in the opening in the bit head and projecting upwardly of the upper end of the pin, the external diameter of said tube being substantially less than that 4of the recess in the pin; anda tubular sub adapted to be connected to the lower end off a pipe string and having an internally threaded box at the lower end in which said pin is threadably received, the extern-alV diameter of said sub being substantially uniform throughout its length, the passage through the sub being of substantiallyV the same diameter as -v the diameter of the recess of said pin, saidv sub having a plurality of annularly spaced openings in the wall thereof upwardly ofthe box and in the same plane relative to each other, said tube extending upwardly into the, passage of the sub and said openings being inclined inwardly and :upwardly with the inner bit including a head with an .axial ends thereof spaced downwardly of the upper end of said tube, gaseous fluid passing downwardly in the well at the outer sides of the sub owing upwardly through the tube Iand also through the -openings in the sub and passing upwardly about the tube to elect reduced pressure at the upper'end of said tube.

2. In apparatus for drilling wells and the like: a rotary opening therethrough; an externally threaded pin extending upwardly from the upper end of said head and having an upwardly opening recess therein; 4an upwardly extending tube having a lower end portion secured in the opening in the bit head and projecting upwardly of the upper end of the pin, the external diameter of said tube being substantially less than that of the recess in the pin; a tubular member of substantially uniform external diameter throughout yits length Iand having ran internally threaded box at the lower end in which said pin is threadably received, the passage through said member being of substantially the same diameter as the diameter of said recess, said member having a plurality of annularly spaced openings in the wa-ll thereof inwardly of the box and inclined inwardly and upwardly, the inner ends of said openings 'being spaced downwardly of the upper end of said tube,

gaseous iluid passing downwardly in the well at the outer sides of the member ilowing upwardly through the tube and also through the openings in the member and passing upwardly about the tube.

3. `In apparatus lfor drilling wells and the like: a rotary bit including a head with a longitudinal opening therethrough; an upwardly extending tube secured in the opening in the bit head and projecting upwardly thereof; van elongated member secured to said bit, said member having a passage therethrough of substantially greater diameter than the externa-l 4diameter of the tube, said tube being disposed .in said passage and defining, with the inner wall of the elongated member, an annular space, said member having Ia substantially uniform configuration throughout its length and having a plurality `of annularly spaced openings in the wall thereof inclined inwardly and upwardly and discharging directly into .the

annular space of said tube; and means releasably connecting the Ibit to the lower end of said elongated member.

4. In apparatus for drilling wells and theV like with gaseous-like drilling fluid: a rotary bit including a head with a longitudinal opening therethrough; connecting means extending upwardly from the upper end of saidV head; 4an upwardly extending tube secured in the opening in the bit head and projecting upwardly of said connecting means; and a tubular member of substantially uniform diameter throughout its length and having a part at the lower end connectible with said connecting means, the passage through said member being of substantially greater diameter than the external diameter of the tube, thereby delining -a relatively large annular passage between said tube `and the wall of the passage Vthrough said member, said member having 'a plurality of annularly spaced openings in the |wall thereof discharging directly upwardly and inwardly about said tube.

References Cited in the le of this patent UNITED STATES PATENTS 626,761 Leyner .lune '13, 1899 1,346,939 Carmichael July 20, 1920 1,850,143 Schu-rmeyer May 22, 1932' 2,421,997 C-rake lune 10, 1947 2,485,998 Johnson Oct. 18, 1949V 2,546,586 Cross Mar. 27, 1951 2,574,717 Stokes Nov. 13, 1951 2,729,426 Smith Jan. 3, 1956 2,849,213 Failing Aug. 26, 1958 

1. APPARATUS FOR DRILLING WELLS AND THE LIKE, COMPRISING: A ROTARY BIT HAVING A HEAD WITH AN AXIAL OPENING THERETHROUGH, SAID HEAD HAVING DEPENDING ARMS, CUTTER ELEMENTS OPERABLY MOUNTED ON SAID ARMS, AND AN EXTERNALLY THREADED PIN EXTENDING UPWARDLY FROM THE UPPER END OF SAID HEAD AND HAVING AN UPWARDLY OPENING RECESS THEREIN; AN UPWARDLY EXTENDING TUBE SECURED IN THE OPENING IN THE BIT HEAD AND PROJECTING UPWARDLY OF THE UPPER END OF THE PIN, THE EXTERNAL DIAMETER OF SAID TUBE BEING SUBSTANTIALLY LESS THAN THAT OF THE RECESS IN THE PIN; AND A TUBULAR SUB ADAPTED TO BE CONNECTED TO THE LOWER END OF A PIPE STRING AND HAVING AN INTERNALLY THREADED BOX AT THE LOWER END IN WHICH SAID PIN IS THREADABLY RECEIVED, THE EXTERNAL DIAMETER OF SAID SUB BEING SUBSTANTIALLY UNIFORM THROUGHOUT ITS LENGTH, THE PASSAGE THROUGH THE SUB BEING OF SUBSTANTIALLY THE SAME DIAMETER AS THE DIAMETER OF THE RECESS OF SAID PIN, SAID SUB HAVING A PLURALITY OF ANNULARLY SPACED OPENINGS IN THE WALL THEREOF UPWARDLY OF THE BOX AND IN THE SAME PLANE RELATIVE TO EACH OTHER, SAID TUBE EXTENDING UPWARDLY INTO THE PASSAGE OF THE SUB AND SAID OPENINGS BEING INCLINED INWARDLY AND UPWARDLY WITH THE INNER ENDS THEREOF SPACED DOWNWARDLY OF THE UPPER END OF SAID TUBE, GASEOUS FLUID PASSING DOWNWARDLY IN THE WELL AT THE OUTER SIDES OF THE SUB FLOWING UPWARDLY THROUGH THE TUBE AND ALSO THROUGH THE OPENINGS IN THE SUB AND PASSING UPWARDLY ABOUT THE TUBE TO EFFECT REDUCED PRESSURE AT THE UPPER END OF SAID TUBE. 